A new SOD mimic, Mn(III) ortho N-butoxyethylpyridylporphyrin, combines superb potency and lipophilicity with low toxicity

The Mn porphyrins of k(cat)(O(2)(.-)) as high as that of a superoxide dismutase enzyme and of optimized lipophilicity have already been synthesized. Their exceptional in vivo potency is at least in part due to their ability to mimic the site and location of mitochondrial superoxide dismutase, MnSOD. MnTnHex-2-PyP(5+) is the most studied among lipophilic Mn porphyrins. It is of remarkable efficacy in animal models of oxidative stress injuries and particularly in central nervous system diseases. However, when used at high single and multiple doses it becomes toxic. The toxicity of MnTnHex-2-PyP(5+) has been in part attributed to its micellar properties, i.e., the presence of polar cationic nitrogens and hydrophobic alkyl chains. The replacement of a CH(2) group by an oxygen atom in each of the four alkyl chains was meant to disrupt the porphyrin micellar character. When such modification occurs at the end of long alkyl chains, the oxygens become heavily solvated, which leads to a significant drop in the lipophilicity of porphyrin. However, when the oxygen atoms are buried deeper within the long heptyl chains, their excessive solvation is precluded and the lipophilicity preserved. The presence of oxygens and the high lipophilicity bestow the exceptional chemical and physical properties to Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin, MnTnBuOE-2-PyP(5+). The high SOD-like activity is preserved and even enhanced: log k(cat)(O(2)(.-))=7.83 vs 7.48 and 7.65 for MnTnHex-2-PyP(5+) and MnTnHep-2-PyP(5+), respectively. MnTnBuOE-2-PyP(5+) was tested in an O(2)(.-) -specific in vivo assay, aerobic growth of SOD-deficient yeast, Saccharomyces cerevisiae, where it was fully protective in the range of 5-30 μM. MnTnHep-2-PyP(5+) was already toxic at 5 μM, and MnTnHex-2-PyP(5+) became toxic at 30 μM. In a mouse toxicity study, MnTnBuOE-2-PyP(5+) was several-fold less toxic than either MnTnHex-2-PyP(5+) or MnTnHep-2-PyP(5+).

Generation of photorealistic 3D image using optical digitizer

A technique to generate a photorealistic three-dimensional (3D) image and color-textured model using a dedicated optical digitizer is presented. The proposed technique is started with the range and texture image acquisition from different viewpoints, followed by the registration and integration of multiple range images to get a complete and nonredundant point cloud that represents a real-life object. The accuracy of the range image and the precision of correspondence between the range image and texture image are guaranteed by sensor system calibration. Based on the point cloud, a geometric model is established by considering the connectivity of adjacent range image points. In order to enhance the photorealistic effect, we suggest a texture blending technique that utilizes a composite-weight strategy to blend the texture images within the overlapped region. This technique allows more efficient removal of the artifacts existing in the registered texture image, leading to a 3D image with photorealistic quality and color-texture modeling. Experimental results are also presented to testify to the validity of the proposed method.

Long-term outcomes and predictors of chronic insomnia: a prospective study in Hong Kong Chinese adults

OBJECTIVES

We aimed to determine the longitudinal course and outcome of chronic insomnia in a five-year prospective study in Hong Kong Chinese adults.

METHODS

Two thousand three hundred and sixteen middle-aged adults (53.3% females, 46.3 ± 5.1 years old at follow-up) were recruited at baseline and follow-up. Participants were divided into three groups: non-insomnia, insomnia symptoms, and insomnia syndrome (insomnia symptoms plus daytime symptoms). Upper airway inflammatory diseases, mental problems, and medical problems were additionally assessed at follow up.

RESULTS

The incidence of insomnia (symptoms and syndrome) was 5.9%. The persistence rate of insomnia syndrome was 42.7% for insomnia syndrome and 28.2% for insomnia symptoms. New incidence of insomnia was associated with younger age, unemployment, and daytime symptoms, while persistence of insomnia was associated with female sex, lower education level, and daytime symptoms at the baseline (p<0.05). Baseline insomnia syndrome was significantly associated with upper airway inflammatory diseases (including asthma and laryngopharyngitis; adjusted OR=1.97-17.9), mental problems, and medical conditions (including arthritis, psychiatric disorders, chronic pain, and gastroesophageal reflux disease; AOR=2.29-3.77), whereas baseline insomnia symptoms were associated with poor mental health (AOR=2.43), psychiatric disorders (AOR=2.39), and chronic pain (AOR=2.95).

CONCLUSIONS

Chronic insomnia is a common problem with considerable persistence and incidence rates among middle-aged Chinese adults. Insomnia syndrome has a higher persistence rate with more mental and medical comorbidities when compared with insomnia symptoms without daytime consequences.

Insomnia, sleep quality, pain, and somatic symptoms: sex differences and shared genetic components

This study investigated the sex differences, and the shared genetic and environmental factors underlying the associations of sleep disturbances (insomnia and sleep quality) with pain and somatic symptoms in both adolescents and middle-aged adults. We recruited 259 adolescents (69 with current insomnia) and their parents (256 middle-aged adults, 78 with current insomnia). Insomnia severity and sleep quality were measured by the Insomnia Severity Inventory (ISI) and Pittsburgh Sleep Quality Index (PSQI), respectively. Pain and somatic symptoms were measured by the Somatic Symptom Inventory and Visual Analogue Scale for overall pain. Subjects with insomnia scored higher on all measures of pain and somatic symptoms than non-insomnia patients, in both adolescents and adults (P<.001). Both pain and somatic measures were associated with ISI and PSQI scores after controlling for age, sex, depressive and anxiety symptoms. There was an interaction effect between insomnia and female sex on pain and somatic symptoms (P<.05), especially in adults. Pain and somatic symptoms ran in family with moderate heritability (range h(2)=0.15-0.42). The phenotypic associations of ISI and PSQI with pain and somatic measures were both contributed by genetic (range p(G)=0.41-0.96) and environmental (range p(E)=0.27-0.40) factors with a major genetic contribution. In summary, insomnia and poor sleep quality are closely associated with pain and somatic symptoms. Insomnia seems to modulate the sex differences in pain and somatic symptoms, especially in the adult population. A shared genetic predisposition might underlie the associations of insomnia and sleep quality with pain and somatic symptoms.

A systematic review and meta-analysis: tailoring asthma treatment on eosinophilic markers (exhaled nitric oxide or sputum eosinophils)

Asthma severity and control can be measured both subjectively and objectively. Traditionally asthma treatments have been individualised using symptoms and spirometry/peak flow. Increasingly treatment tailored in accordance with inflammatory markers (sputum eosinophil counts or fractional exhaled nitric oxide (FeNO) data) is advocated as an alternative strategy. The objective of this review was to evaluate the efficacy of tailoring asthma interventions based on inflammatory markers (sputum analysis and FeNO) in comparison with clinical symptoms (with or without spirometry/peak flow) for asthma-related outcomes in children and adults. Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and reference lists of articles were searched. The last searches were in February 2009. All randomised controlled comparisons of adjustment of asthma treatment based on sputum analysis or FeNO compared with traditional methods (primarily clinical symptoms and spirometry/peak flow) were selected. Results of searches were reviewed against predetermined criteria for inclusion. Relevant studies were selected, assessed and data extracted independently by at least two people. The trial authors were contacted for further information. Data were analysed as 'intervention received' and sensitivity analyses performed. Six (2 adults and 4 children/adolescent) studies utilising FeNO and three adult studies utilising sputum eosinophils were included. These studies had a degree of clinical heterogeneity including definition of asthma exacerbations, duration of study and variations in cut-off levels for percentage of sputum eosinophils and FeNO to alter management in each study. Adults who had treatment adjusted according to sputum eosinophils had a reduced number of exacerbations compared with the control group (52 vs. 77 patients with ≥1 exacerbation in the study period; p=0.0006). There was no significant difference in exacerbations between groups for FeNO compared with controls. The daily dose of inhaled corticosteroids at the end of the study was decreased in adults whose treatment was based on FeNO in comparison with the control group (mean difference -450.03 μg, 95% CI -676.73 to -223.34; p<0.0001). However, children who had treatment adjusted according to FeNO had an increase in their mean daily dose of inhaled corticosteroids (mean difference 140.18 μg, 95% CI 28.94 to 251.42; p=0.014). It was concluded that tailoring of asthma treatment based on sputum eosinophils is effective in decreasing asthma exacerbations. However, tailoring of asthma treatment based on FeNO levels has not been shown to be effective in improving asthma outcomes in children and adults. At present, there is insufficient justification to advocate the routine use of either sputum analysis (due to technical expertise required) or FeNO in everyday clinical practice.

Endovascular embolization for deep Basal Ganglia arteriovenous malformations

We report our experience with basal ganglia AVM embolization and clinical outcomes after embolization. We retrospectively evaluated consecutive 15 patients with AVMs in the basal ganglia with respect to the endovascular treatment of these lesions. Treatment consisted of embolization and radiosurgery in combination. The angiographic follow-up after the last management was 24-36 months (mean 27 months). Clinical follow-up monitoring (range, 24-120 months, mean 76 months) was measured by the Modified Rankin Scale (mRS). The 15 patients studied had a mean age of 25.1 years at diagnosis, and 33.3% were male. Intracranial hemorrhage (ICH) was the event leading to clinical detection in eight patients (53.3%), and 85.5% of these patients were left with hemiparesis. At presentation, eight (53.3%) patients bled a total of 11 times. Twenty-four embolization procedures (16 pedicles embolized) were performed in 15 patients with embolization as the adjunct to radiosurgery. There were three clinically significant complications. Excellent or good outcomes (mRS≤2) were observed in 13 (86.7%) patients. Unfavorable outcomes (mRS≤2) were 13.3% at follow-up, without mortality. Seven (46.7%) patients had complete AVM obliteration at follow-up. The risk of incurring a neurological deficit with basal ganglia AVM is high. Treatment of these patients is endovascular embolization with a combination of radiosurgery to prevent neurological injury from a spontaneous ICH.

Natural history and predictors for progression of mild childhood obstructive sleep apnoea

AIMS

The natural history of mild childhood obstructive sleep apnoea (OSA) was examined and factors associated with disease progression were identified.

METHODS

Subjects were recruited from an epidemiological study which examined the prevalence of OSA in Chinese children aged 6-13 years. The first 56 consecutive children identified with mild OSA (apnoea-hypopnoea index 1-5) were invited for a repeat assessment 2 years after the diagnosis.

RESULTS

45 children participated in the follow-up study, in 13 of whom (29%) the OSA was found to have worsened. Compared with those in whom OSA had not worsened, the worsened OSA group had a greater increase in waist circumference, a higher prevalence of large tonsils (occupying > or =50% of the airway) at both baseline and follow-up, and a higher prevalence of habitual snoring at both baseline and follow-up. The presence of large tonsils had a positive predictive value of 53% and a negative predictive value of 83% for worsening OSA over a 2-year period. Multivariate linear regression analysis showed that the change in obstructive apnoea-hypopnoea index was associated with age at baseline (beta (SE) = -0.92 (0.34), p = 0.009), gender (male = 1; female = 0) (beta (SE) = 4.69 (1.29), p<0.001), presence of large tonsils at baseline (beta (SE) = 4.36 (1.24), p = 0.001), change in waist circumference (beta (SE) = 0.30 (0.09), p = 0.002) and persistently large tonsils (beta (SE) = 5.69 (1.36), p<0.001) over the 2-year period.

CONCLUSIONS

Mild OSA in the majority of children does not resolve spontaneously. Subjects with tonsillar hypertrophy, especially boys, should be closely monitored to allow early detection of worsening OSA. Weight control should be stressed in the management of childhood OSA.

A community-based study of insomnia in Hong Kong Chinese children: Prevalence, risk factors and familial aggregation

OBJECTIVES

There has been limited data on familial aggregation of insomnia. We aimed to explore the prevalence, risk factors and familial aggregation of childhood insomnia with a large community-based sample.

METHODS

A community-based epidemiologic study of sleep disorders was conducted among primary school children. Those children with at least one reported biological parent were recruited. A total of 5695 children (mean age 9.2; SD 1.8), 4939 of their reported biological mothers (mean age 38.9; SD 4.6) and 4289 of their reported biological fathers (mean age 43.3; SD 5.5) were studied.

RESULTS

The rates of insomnia 3 times/week in the past 12 months were 4.0%, 12.8% and 9.7% for children, mothers and fathers, respectively. A robust familial aggregation of insomnia was found even after adjustment of the shared environmental and socio-demographic factors. There was a significant dose-response relationship among the children across their parental status from neither, fathers, mothers to both parents with insomnia [3.0%, 7.1%, 9.5% and 11.9%; with ORs (95% CIs)=2.48 (1.82-4.37) for fathers, 3.42 (2.55-4.59) for mothers and 4.42 (2.42-8.10) for both parents, respectively]. In addition, the frequency of insomniac symptoms of the parents also had a dose-response effect on the rate of insomnia of their children.

CONCLUSIONS

Insomnia is a common problem in both children and their parents. A significant familial aggregation of childhood onset insomnia was seen in this study even after adjustment of the co-risk factors. There was a dose-response effect of parental insomnia on the rate of insomnia of their children with a slight predilection of maternal influences.

Wavefront reconstruction and three-dimensional shape measurement by two-step dc-term-suppressed phase-shifted intensities

A wavefront reconstruction and three-dimensional (3-D) shape measurement method by a two-step phase-shifting algorithm with arbitrary phase shift in (0,pi) is proposed. In this method, only two phase-shifted intensities, with the removal of the dc term by an averaging technique in spatial domain or low-pass filter operation in the frequency domain, are needed, and the other additional measurements are no longer required. The simulation for an irregular wavefront has shown the feasibility, and the optical experiment for a 3-D face mask in the case of a sinusoidal fringe projection system has illustrated the validity of the proposed method.

Identification of viral and atypical bacterial pathogens in children hospitalized with acute respiratory infections in Hong Kong by multiplex PCR assays

Acute respiratory tract infection is a leading cause of hospital admission of children. This study used a broad capture, rapid and sensitive method (multiplex PCR assay) to detect 20 different respiratory pathogens including influenza A subtypes H1, H3, and H5; influenza B; parainfluenza types 1, 2, 3, and 4; respiratory syncytial virus (RSV) groups A and B; adenoviruses; human rhinoviruses; enteroviruses; human metapneumoviruses; human coronaviruses OC43, 229E, and SARS-CoV; Chlamydophila pneumoniae; Legionella pneumophila; and Mycoplasma pneumoniae; from respiratory specimens of 475 children hospitalized over a 12-month period for acute respiratory tract infections. The overall positive rate (47%) was about twice higher than previous reports based on conventional methods. Influenza A, parainfluenza and RSV accounted for 51%, and non-cultivable viruses accounted for 30% of positive cases. Influenza A peaked at March and June. Influenza B was detected in January, February, and April. Parainfluenza was prevalent throughout the year except from April to June. Most RSV infections were found between February and September. Adenovirus had multiple peaks, whereas rhinovirus and coronavirus OC43 were detected mainly in winter and early spring. RSV infection was associated with bronchiolitis, and parainfluenza was associated with croup; otherwise the clinical manifestations were largely nonspecific. In general, children infected with influenza A, adenovirus and mixed viruses had higher temperatures. In view of the increasing concern about unexpected outbreaks of severe viral infections, a rapid multiplex PCR assay is a valuable tool to enhance the management of hospitalized patients, and for the surveillance for viral infections circulating in the community.

Cardiac remodelling and dysfunction in children with obstructive sleep apnoea: a community based study

BACKGROUND

Childhood obstructive sleep apnoea (OSA) is suggested to be associated with cardiac structural abnormalities and dysfunction but existing evidence is limited and the treatment effect on echocardiographic outcome remains controversial.

OBJECTIVE

To examine the presence of subclinical cardiac abnormalities in childhood OSA and the effects of treatment on cardiac changes.

METHODS

Polysomnography (PSG) and echocardiographic examinations were performed in 101 children aged between 6 and 13 years who were invited from a community based questionnaire survey. They were classified into a reference group (apnoea-hypopnoea index (AHI) <1, n = 35), mild OSA group (AHI 1-5, n = 39) and moderate to severe group (AHI >5, n = 27) based on the PSG results. Treatments, including adenotonsillectomy or nasal steroids, were offered to the mild and moderate to severe OSA groups.

RESULTS

The moderate to severe OSA group had greater right ventricular (RV) systolic volume index (RVSVI), lower RV ejection fraction (RVEF) and higher RV myocardial performance index (RVMPI) than the reference group. They also had more significant left ventricular (LV) diastolic dysfunction and remodelling with larger interventricular septal thickness index (IVSI) and relative wall thickness than those with lower AHI values. The moderate to severe OSA group had an increased risk of abnormal LV geometry compared with the reference group (odds ratio 4.21 (95% CI 1.35 to 13.12)). Log transformed AHI was associated with RVSVI (p = 0.0002), RVEF (p = 0.0001) and RVMPI (p<0.0001), independent of the effect of obesity. Improvement in RVMPI, IVSI and E/e' were observed in those with a significant reduction in AHI (>50%) comparing 6 month with baseline data.

CONCLUSIONS

OSA is an independent risk factor for subclinical RV and LV dysfunction, and improvement in AHI is associated with reversibility of these abnormalities.

Narcolepsy in Southern Chinese patients: clinical characteristics, HLA typing and seasonality of birth

OBJECTIVE

To report clinical characteristics, human leukocyte antigen (HLA) typing and seasonality of birth of a series of 54 Southern Chinese patients suffering from narcolepsy.

METHODS

All subjects underwent detailed medical and psychiatric interviews and a standardised nocturnal polysomnogram followed by a daytime Multiple Sleep Latency Test. Each subject also completed a set of sleep questionnaires. HLA typing was performed in 91% of subjects.

RESULTS

A total of 78% and 22% of patients were diagnosed with suffering from cataplectic and non-cataplectic narcolepsy, respectively. The majority (n = 47, 87%) of patients were referred to our sleep clinic for excessive daytime sleepiness (EDS). The cataplectic narcolepsy differed from non-cataplectic narcolepsy by having more rapid eye movement (REM)-related clinical symptoms (more sleep paralysis and sleep-related hallucination) and sleep disturbances (shorter REM latency), as well as tighter association with HLA DQB1*0602. A bi-modal peak pattern was observed at 11 and 39 years old. A similar bi-modal pattern also occurred for EDS and cataplexy. Excess winter births were observed for this series of patients. 81% of patients with cataplectic narcolepsy were DQB1*0602-positive. There were no differences between early- and late-onset cases in the association with positive DQB1*0602 (71.4% vs 60%). Narcolepsy had prominent pernicious effects on various social, academic, family and mental aspects in our patients.

CONCLUSIONS

In our Southern Chinese narcolepsy series, bi-modal peak pattern of age of onset, excess winter birth and tight association of HLA DQB1*0602 with cataplectic narcolepsy were found.

Tailored interventions based on exhaled nitric oxide versus clinical symptoms for asthma in children and adults

BACKGROUND

The measurement of severity and control of asthma in both children and adults can be based on subjective or objective measures. It has been advocated that fractional exhaled nitric oxide (FeNO) can be used to monitor airway inflammation as it correlates with some markers of asthma. Interventions for asthma therapies have been traditionally based on symptoms and/or spirometry.

OBJECTIVES

To evaluate the efficacy of tailoring asthma interventions based on exhaled nitric oxide in comparison to clinical symptoms (with or without spirometry/peak flow) for asthma related outcomes in children and adults.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and reference lists of articles. The last search was completed in December 2006.

SELECTION CRITERIA

All randomised controlled comparisons of adjustment of asthma therapy based on exhaled nitric oxide compared to traditional methods (primarily clinical symptoms and spirometry/peak flow).

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Relevant studies were independently selected in duplicate. Two authors independently assessed trial quality and extracted data. Authors were contacted for further information but none were received. Data was analysed as "intervention received" and sensitivity analyses performed.

MAIN RESULTS

Four (2 adult and 2 paediatric) studies were included; these studies differed in a variety of ways including definition of asthma exacerbations, FeNO cut off levels and duration of study. Of 356 participants randomised, 324 completed the trials. In the meta-analysis, there was no difference between groups for the primary outcome of asthma exacerbations or for other outcomes (clinical symptoms, FeNO level and spirometry). In post-hoc analysis, a significant reduction in mean final daily dose inhaled corticosteroid per adult was found in the group where treatment was based on FeNO in comparison to clinical symptoms; WMD -282.46 (95% CI -422.08 to -142.84). There was no difference in ICS dose between the groups in the overall daily dose in the adult studies or in the paediatric studies.

AUTHORS' CONCLUSIONS

Tailoring the dose of inhaled corticosteroids based on exhaled nitric oxide in comparison to clinical symptoms was carried out in different ways in the four studies that were found, and the results show only modest differences. The role of utilising exhaled nitric oxide to tailor the dose of inhaled corticosteroids is currently uncertain.

Ambulatory blood pressure in children with obstructive sleep apnoea: a community based study

BACKGROUND

Childhood obstructive sleep apnoea (OSA) is increasingly being recognised. Its effects on blood pressure (BP) elevation and hypertension are still controversial.

OBJECTIVE

To evaluate the association between OSA and ambulatory BP in children.

METHODS

Children aged 6-13 years from randomly selected schools were invited to undergo overnight sleep study and ambulatory BP monitoring after completing a validated OSA questionnaire. OSA was diagnosed if the obstructive apnoea-hypopnoea index (AHI) was >1, and normal controls had AHI <1 and snoring <3 nights per week. Children with OSA were subdivided into a mild group (AHI 1-5) and moderate to severe group (AHI >5).

RESULTS

306 subjects had valid sleep and daytime BP data. Children with OSA had significantly higher BP than normal healthy children during both sleep and wakefulness. BP levels increased with the severity of OSA, and children with moderate to severe disease (AHI >5) were at significantly higher risk for nocturnal systolic (OR 3.9 (95% CI 1.4 to 10.5)) and diastolic (OR 3.3 (95% CI 1.4 to 8.1)) hypertension. Multiple linear regression revealed a significant association between oxygen desaturation index and AHI with daytime and nocturnal BP, respectively, independent of obesity.

CONCLUSIONS

OSA was associated with elevated daytime and nocturnal BP, and is an independent predictor of nocturnal hypertension. This has important clinical implications as childhood elevated BP predicts future cardiovascular risks. Future studies should examine the effect of therapy for OSA on changes in BP.

Tailored interventions based on sputum eosinophils versus clinical symptoms for asthma in children and adults

BACKGROUND

Asthma severity and control can be measured both subjectively and objectively. Sputum analysis for evaluation of percentage of sputum eosinophilia directly measures airway inflammation, and is one method of objectively monitoring asthma. Interventions for asthma therapies have been traditionally based on symptoms and spirometry.

OBJECTIVES

To evaluate the efficacy of tailoring asthma interventions based on sputum analysis in comparison to clinical symptoms (with or without spirometry/peak flow) for asthma related outcomes in children and adults.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and reference lists of articles. The last search was on 31 October 2006.

SELECTION CRITERIA

All randomised controlled comparisons of adjustment of asthma therapy based on sputum eosinophils compared to traditional methods (primarily clinical symptoms and spirometry/peak flow).

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Three sets of reviewers selected relevant studies. Two review authors independently assessed trial quality extracted data. Authors were contacted for further information but none were received. Data was analysed as "treatment received" and sensitivity analyses performed.

MAIN RESULTS

Three adult studies were included; these studies were clinically and methodologically heterogenous (use of medications, cut off for percentage of sputum eosinophils and definition of asthma exacerbation). There were no eligible paediatric studies. Of 246 participants randomised, 221 completed the trials. In the meta-analysis, a significant reduction in number of participants who had one or more asthma exacerbations occurred when treatment was based on sputum eosinophils in comparison to clinical symptoms; pooled odds ratio (OR) was 0.49 (95% CI 0.28 to 0.87); number needed to treat to benefit (NNTB) was 6 (95% CI 4 to 32). There were also differences between groups in the rate of exacerbation (any exacerbation per year) and severity of exacerbations defined by requirement for use of oral corticosteroids but the reduction in hospitalisations was not statistically significant. Data for clinical symptoms, quality of life and spirometry were not significantly different between groups. The mean dose of inhaled corticosteroids per day was similar in both groups and no adverse events were reported. However sputum induction was not always possible.

AUTHORS' CONCLUSIONS

Tailored asthma interventions based on sputum eosinophils is beneficial in reducing the frequency of asthma exacerbations in adults with asthma. This review supports the use of sputum eosinophils to tailor asthma therapy for adults with frequent exacerbations and severe asthma. Further studies need to be undertaken to strengthen these results and no conclusion can be drawn for children with asthma.

Assessing disease burden of respiratory disorders in Hong Kong children with hospital discharge data and linked laboratory data

OBJECTIVES

To describe the pattern of respiratory disorders in the Hong Kong paediatric population admitted to government hospitals, and to assess the reliability of the diagnoses by linkage with laboratory data.

METHODS

Discharge diagnoses for all admissions are recorded in a central computerised database, the Clinical Management System. These data were analysed for the inclusive period July 1997 to June 1999. Virology laboratory results from a single hospital were linked to the Clinical Management System diagnostic codes to examine discrepancies in coding specific viral aetiologies.

RESULTS

A primary diagnosis of a respiratory disorder was noted in 37.5% (upper respiratory 30.1%, tonsillitis/pharyngitis 10.5%, croup/laryngitis 2.3%, acute otitis media 2.7%, bronchitis/chest infection 2.6%, bronchiolitis 10.2%, pneumonia 20.9%, influenza 4%, asthma and allergic rhinitis 16.5%), and a primary or secondary diagnosis in 42.5% of children younger than 15 years. The incidence rates of respiratory illness coded as bronchiolitis and influenza were respectively estimated to be 887-979 and 222-381 per 100,000 children under 5 years and 3551-3949 and 415-528 per 100,000 children under the age of 1 year. The percentage of respiratory-associated admissions varied significantly by hospital and detailed analysis of data at one hospital highlighted important discrepancies between discharge diagnosis and laboratory results.

CONCLUSIONS

These passive surveillance data provide general estimates of the disease burden for respiratory disorders in Hong Kong children. Active surveillance studies are required to provide more accurate estimates of the disease burden. Consideration should be given to enhance the Clinical Management System by routinely linking all laboratory data with discharge diagnosis information, by establishing sentinel surveillance hospitals and by assessing new strategies to standardise coding.

Induced sputum inflammatory measures correlate with disease severity in children with obstructive sleep apnoea

OBJECTIVE

To establish the association between airway inflammation and severity of obstructive sleep apnoea (OSA) in children.

METHODS

Consecutive children presenting with symptoms suggestive of OSA were recruited. They completed a sleep apnoea symptom questionnaire, underwent physical examination, spirometry, sputum induction and an overnight polysomnography. Adequate sputum contained <50% squamous epithelial cells, and OSA was diagnosed if the obstructive apnoea index was >1.

RESULTS

73 children with a median (interquartile range (IQR)) age of 11.3 (10.0-13.2) years were recruited. There were 21 girls and the median body mass index of the group was 24.0 (18.0-27.0) kg/m2. The most common presenting symptoms were habitual snoring, mouth breathing and prone sleeping position. Sputum induction was successful in 43 (59%) children, of whom 14 were found to have OSA. Children with OSA had significantly greater percentage sputum neutrophil than those without OSA (18.5 (IQR 8.0-42.0) v 4 (IQR 3.0-11.3), p = 0.006). On multiple regression analysis, percentage sputum neutrophil was significantly associated with OSA (odds ratio = 1.1, p = 0.013).

CONCLUSION

Children with OSA had airway inflammation characterised by a marked increase in neutrophils. Further studies are needed to confirm these findings and to better define the downstream cellular interactions and molecular pathogenesis in childhood OSA.

Cough frequency in children with mild asthma correlates with sputum neutrophil count

BACKGROUND

A study was undertaken to measure cough frequency in children with stable asthma using a validated monitoring device, and to assess the correlation between cough frequency and the degree and type of airway inflammation.

METHODS

Thirty six children of median age 11.5 years (interquartile range (IQR) 9-14) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring for 24 hours. Coughing episodes were counted both as individual spikes and as clusters.

RESULTS

All children had mild intermittent asthma and their median forced expiratory volume in 1 second and eNO were 83.3% (IQR 81.1-97.6) and 56.1 ppb (IQR 37.4-105), respectively. The median number of cough episodes per day was 25.5 (IQR 16-42.8). Sputum induction was successful in 69% of the subjects and cough frequency was found to have a significant positive correlation with sputum neutrophil count (r = 0.833, p = 0.0001).

CONCLUSIONS

Children with stable mild asthma have increased cough frequency that might be driven by a neutrophilic inflammatory pathway.

Longer term follow up of aerobic capacity in children affected by severe acute respiratory syndrome (SARS)

BACKGROUND

A study was undertaken to investigate the aerobic capacity and pulmonary function of children 6 and 15 months after the diagnosis of severe acute respiratory syndrome (SARS).

METHODS

Thirty four patients of mean age 14.7 years completed both pulmonary function and maximal aerobic capacity tests at 6 months. All had normal clinical examination and were asymptomatic. Their exercise responses were compared with a group of healthy controls. Complete data were collected on 27 of the original 34 cases at 15 months.

RESULTS

Compared with normal controls, the patient group had significantly lower absolute and mass related peak oxygen consumption (peak V o(2) (p<0.01)), higher ventilatory equivalent for oxygen (p<0.01), lower oxygen pulse (p<0.01), and a lower oxygen uptake efficiency slope (p<0.01) at 6 months. This impairment was unexpected and out of proportion with the degree of lung function abnormality. Residual high resolution computed tomography of thorax (HRCT) abnormalities were present in 14 patients. Those with abnormal HRCT findings had significantly lower mass related peak V o(2) than subjects with normal radiology (p<0.01). Absolute and mass related peak V o(2) in the patient group remained impaired at 15 months despite normalisation of lung function in all patients.

CONCLUSIONS

The mechanism for the reduced aerobic capacity in children following SARS is not fully understood, but it is probably a consequence of impaired perfusion to the lungs at peak exercise and deconditioning.

Deletion of the nuclear receptor Nr2e1 impairs synaptic plasticity and dendritic structure in the mouse dentate gyrus

The spontaneous or targeted deletion of the nuclear receptor transcription factor Nr2e1 produces a mouse that shows hypoplasia of the hippocampal formation and reduced neurogenesis in adult mice. In these studies we show that hippocampal synaptic transmission appears normal in the dentate gyrus and cornu ammonis 1 subfields of adult mice that lack Nr2e1 (Nr2e1-/-), and that fEPSP shape, paired-pulse responses, and short-term plasticity are not substantially altered in either subfield. In contrast, the expression of long-term potentiation is selectively impaired in the dentate gyrus, and not in the cornu ammonis 1 subfield. Golgi analysis revealed that there was a significant reduction in both dendritic branching and dendritic length that was specific to dentate gyrus granule cells in the Nr2e1-/- mice. These results indicate that Nr2e1 deletion can significantly alter both synaptic plasticity and dendritic structure in the dentate gyrus.

Severe acute respiratory syndrome (SARS) in neonates and children

Severe acute respiratory syndrome (SARS) runs a more benign course in children during the acute phase. Infants born to mothers with the disease did not acquire the infection through vertical transmission. The treatment strategy for children with SARS has not been standardised and is based on adult experience. Thus far, no deaths have been reported in the paediatric age group. Exercise impairment and residual radiological abnormalities were present six months after diagnosis. It is important to assess these patients on a regular basis to detect and provide appropriate management for any persistent or emerging long term sequelae in the physical, psychological, and social domains. This review describes the current understanding of SARS coronavirus infection in newborns and children.

The six-minute walk test in healthy children: reliability and validity

The aim of this study was to assess the reliability and validity of the 6-min walk test (6MWT) in healthy children. Chinese secondary school students were randomly recruited. They attended the current authors' unit on two occasions, separated by 2 weeks. Physical examination and standardised maximum incremental exercise testing on a treadmill were performed on the first visit. Spirometry and 6MWT were carried out on the second visit. A randomly selected subgroup was invited to return for repeat 6MWT at an interval of 2-4 weeks. Seventy-eight subjects were recruited; however, four failed to achieve maximal effort on exercise test. The final group included 43 young females and the mean+/-sd age of the subjects was 14.2+/-1.2 yrs. Physical examination was unremarkable in all cases. The mean+/-sd per cent predicted forced expiratory volume in one second was 91.4+/-10.2%. Concurrent validity was demonstrated by good correlation between the 6-min walking distance and maximum oxygen uptake determined on the exercise treadmill. Test-retest reliability was undertaken in 52 subjects, and the intraclass correlation coefficient (95% confidence interval) was calculated as 0.94 (0.89-0.96). In addition, Bland and Altman plots demonstrated a high degree of repeatability. In healthy children, the 6-min walk test is a reliable and valid functional test for assessing exercise tolerance and endurance.

Induced sputum in childhood asthma

Asthma is characterised by variable degrees of airway obstruction, airway hyper-responsiveness, and chronic airway inflammation. Current guidelines emphasise that inhaled corticosteroid treatment is the mainstay of asthma therapy because it targets the underlying airway inflammation. It is prudent to use the lowest possible dose of inhaled corticosteroid compatible with good asthma control. In clinical practice, the use of or the reduction of inhaled corticosteroid dosage is based on symptoms and lung function, both of which have been shown to have a poor correlation with airway inflammation. The use of induced sputum as a marker of airway inflammation improves asthma monitoring and optimises treatment in adults. This review discusses the technique of sputum induction, its clinical application, and our experience of its use in asthmatic children.